Is It Carbs or Is It Fats?

Are we fat because we eat too many carbs or too many fats?

The ‘low carb’ camp says that the best way to eliminate obesity is to cut out carbs and sugar. They maintain two premises:

Low-fat diets have not worked. Even though the US Department of Agriculture (USDA) Dietary Guidelines have recommended a low-fat diet for decades, we still keep getting fatter and fatter.

Carbs increase glucose (and insulin) levels, which in turn makes us fat. If we lower our carbohydrates intake, we decrease our glucose levels as well as our fat gain.

Let’s look at each of these claims carefully.

The first statement suggests that if the low-fat approach has not worked, we must be fat for another reason.

The low carb contingency points their finger at our excessive intake of carbs.

Are they right?

To evaluate, let’s look at our daily consumption of calories and nutrients to see how our diet changed between 1970 and 2010:

For starters, we now eat almost 500 extra calories a day!

Our sugar intake has increased by only 40 calories (12 percent) although our grain consumption has soared by 42 percent. However, the grains we refer to here are mostly refined grains, stripped of their fiber and nutrients versus the nourishing intact whole grains that the USDA recommends (Remember that 90% of the carbohydrates in the Standard American Diet are refined!)

Our intake of dairy has slightly decreased (13 calories), but cheese consumption has risen 153 percent. This suggests we have swapped out milk for cheese, which is problematic since cheese is the number one source of saturated fats in the American diet and very high in sodium.

Meat intake has barely changed over this time period (Although we started at elevated levels; American consumption of meat continues to be one of the highest in the world.)

The amount of fruit and veggies in our diet remained relatively unchanged, which means we continue to not eat enough of them. Only 4 percent of Americans eat the minimum 6-8 servings of fruits and vegetables every day. Our consumption of beans (which falls in this category) is particularly low.

Which brings us to fats—the part of our diet that has changed the most. Between 1970 and 2010, our fat intake increased 67 percent!

Another way of looking at this is that almost half of those extra 500 calories we eat each day come from fat (while another 37 percent comes from refined (not whole) grains).

That is a lot of fat.

So while the Dietary Guidelines might have recommended Americans consume less fat, we clearly did not listen.

These numbers tell a clear story.

Our obesity problem is caused primarily by an overconsumption of fats and oils and, to a lesser extent, refined, processed carbohydrates.

What About Glucose?

An excess ingestion of carbohydrates spikes glucose levels in the bloodstream.

In turn, elevated glucose increases insulin levels.

Raised insulin then triggers an increase in fat storage.

According to this interpretation, the only way to ‘fix’ the situation is to eat a low-carb diet; by eating fewer carbs, your glucose and insulin levels will be lower, and you will not gain weight (fat).

This ‘low carb’ line of reasoning is flawed because it assumes incorrectly that only carbohydrates elevate insulin when, in fact, high protein and high fat foods or their addition to carbohydrate-rich meals will raise insulin as well (without an increase in blood glucose levels).

In other words, insulin response is not always proportional to blood glucose levels or to the carbohydrate content of a meal.

If you eat a diet high in fat (and low in carbohydrates), insulin may ‘instruct’ your body to burn fat instead of carbohydrates. However, it will not dip into your fat stores any more (or any less) than if your diet is based on carbohydrates.

As long as the calories consumed are close to or in excess of what you need, fat storage will remain the same.

The best way out is to reduce the consumption of fats (especially saturated fats found in animal-based foods and plant-based tropical fats and oils) and revert to a low-fat, whole food, plant-based diet.

This will stop the downward spiral by replacing your previous energy-dense diet with one naturally low in calories and yet high in nutritional density. Equally, it will ensure that the carbohydrates you eat are the right kind (i.e. ‘intact’ and unprocessed).

Obesity may be a daunting enemy but through the proper diet (lifestyle), it can indeed be conquered.

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Rosane Oliveira, DVM, PhD

Rosane Oliveira, DVM, PhD is Founding Director of UC Davis Integrative Medicine and Adjunct Assistant Professor at the Department of Public Health Sciences at the School of Medicine at the University of California Davis. Blending a life-long passion for food and nutrition with over 20 years of scientific experience in genetic research, Dr. Oliveira is devoted to educating people about how food and lifestyle choices can affect genetic expression–i.e. how genes are turned on and off and either cause disease or promote health. She is a native of Rio de Janeiro, Brazil and has lived in the US since 2003.